Power transmission for reversible machine elements



Jam. =3, 394%. c. z. MQNRQE EOWER TRANSMISSION FOR REVERSIBLE MACHINEELEEENTS 4 Shams-Sheet 1 Filed April 10,, 1944 N V B NTo k 6&af/es ZQf/anrae 6M4, I W 1 (0% a I O0 "r-ro REYJ Z. MQNRE POWER TRANSMISSIONFOR REVERSIBLE MACHINE ELEMENTS 4. Sheets-Sheet 2 Filed April 10, 194-4d V E N To M O/zar/ea Z Waxy/0e Jam. 149.,

mmsmssxw NR navmsmm Z. MONRQE POWER EQACHINE ELEMENTS Shams-Sham 5 FiledApril 10, 1944 fi 0 J Q W QQ 7. 1 a W Y RQI Q I M? a NZ m3 5 W 6v W W Q59 w a o h N W m Y u N M mm mm mm Nb mi E m Jam 4'1, HQQQQ z. MQNRQEPOWER TRANS ZAQEQ MISSION FOR nmvmsmm MACHINE ELEMENTS Filed April 10,1944 Patented Jan. 4, 1949 UNETE ELERENTS Charles Z. Monroe, Detroit,Mich, assignor to Ex-Cell-Q Corporation, Detroit, Mich, a. corporationof Michigan Application April 10, 1944, Serial No. 539,275

19 Claims. 1

The present invention relates generally to improvements in powertransmissions for driving reversible machine elements, and hasparticular reference to a new and improved transmission for translatinga reversibly operable machine tool element, such as a reciprocatorycarriage or table, adapted to be translated selectively at differentrates of speed.

Machine tool carriages and similar elements are normally reciprocatedback and forth through a predetermined working range, and at a rate oftraverse adjustable in accordance with the requirements of the machiningoperation to be performed. Due to their comparatively heavy weight,machine tool carriages will overrun the point at which reversal isinitiated, and this overrun will vary considerably in extent if reversalis effected at different speeds. The primary object of the invention isto. provide a novel power transmission which will cause the reciprocablecarriage or other element to have a constant predetermined overrun atreversal, so that reversal will always occur at a definite pointregardless of the rate of traverse during the normal travel.

Another object is to provide a new and improved power transmission inwhich the normal rate of traverse is adjustable between minimum andmaximum limits, and which is automatically operable to decelerate therate to a predetermined fixed value substantially at or below saidminimum immediately preceding and for each reversal of the drivenelement, and after each reversal to accelerate the rate immediately backto normal.

Another object is to provide a novel power transmission of the foregoingcharacter in which the extent of movement of the driven elementimmediately preceding reversal and during which deceleration occursvaries in accordance with the normal adjustable rate of traverse.

Further objects and advantages will become apparent as the descriptionproceeds.

In the accompanying drawings,

Figure 1 is a front elevational view of a machine having a powertransmission for a reciprocatory carriage embodying the features of myinvention.

Fig. 2 is a diagrammatic representation of the power transmission.

Fig. 3 is a Vertical sectional view, taken along line 3-3 of Fig. 1, ofa unitary control panel forming part of the transmission.

Fig. 4 is a fragmentary vertical sectional view of the control paneltaken substantially along line 4-4 of Fig. 3, and illustrating thedirection control means in condition to eifect reversal of the carriage.

Fig. 5 is a view similar to Fig. 4, but with certain portions brokenaway to illustrate more clearly the direction control means in thecondition immediately following reversal.

Figs. 6 and '7 are transverse sectional views taken respectively alonglines 6% and 1? of Figs. 3 and 4, respectively.

Fig. 8 is a rear face view of a rotary cam forming part of the speedcontrol means.

Fig. 9 is a velocity diagram illustrating the deceleration of thecarriage movement prior to reversal.

Referring more particularly to the drawings, the power transmission,constituting the exemplary embodiment of the invention, is adapted foruse in driving various types of reversibly movable machine elements,and, for the purposes of illustration, is shown applied to thereciprocatory table or carriage l of a grinding machine.

The machine, illustrated in Fig. 1, comprises a horizontal base 2 formedon the top with longi tudinal ways 3 on which the carriage l is slidablymounted. In the present instance, the carriage I is adapted to support aworkpiece (not shown) for reciprocation in opposite directions past asurface grinding wheel t, but it is to be understood that the inventionis not limited to a machine element having a rectilinear movement, noran element for any particular purpose in any specific type of machine.

The grinding Wheel 4 is supported for rotary drive in a suitable toolhead 5 mounted on a vertical column 6 on the rear of the base 2. Thedetails of the support and drive for the grinding wheel 5 form no partof the present invention, and hence are not fully disclosed. It issufficient to state that the column 6 is horizontally adjustabletransversely of the carriage l to locate the grinding wheel 4 in propercutting position, and that the head 5 is adjustable vertically on thecolumn to the desired depth of cut.

The invention relates to a power transmission adapted to reciprocate thetable or carriage I automatically through an adjustable working range.In general, the transmission may be of an suitable type comprising avariable-speed reversible motor connected to drive the carriage i. Thetransmission includes a direction control means adapted for actuation bythe carriage I upon movement into a predetermined position at each endof the reciprocation to reverse the operation of the drive motor andthereby reverse the direction of traverse. The transmission alsoincludes an adjustable control means for determining the speed at whichthe motor will operate in either direction of carriage movement. Thespeed control means is selectively adjustable to effect translation ofthe carriage atany desired rate over a range from a slow minimum speedprogressively to a fast maximum speed depending on the requirements ofthe machining operation to be performed. Additional means is providedfor automatically adjusting the speed control means from the selectednormal speed setting at any point within the speed range to the minimumspeed setting so as to decelerate the carriage movement to a fixed lowrate immediately preceding each reversal of the carriage. The extent ofmovement preceding reversal and during which the carriage is deceleratedvaries in accordance with the degree of deceleration required to bringthe speed down to the low rate. Regardless for what selected rate ofnormal movement the speed control means may be set. the carriage willalways be traveling at the fixed low rate when the direction controlmeans is actuated to effect reversal, and therefore will always reverseat a predetermined flxed point. Concurrently with such reversal, thedeceleration control means is rendered inefiective so as to acceleratethe carriage speed immediately back to the normal rate.

The table or carriage I may be shifted or fed mechanically by means (notshown) having an operating hand wheel I, and the particular transmissionherein disclosed for translating the carriage in an automati reversingcycle is operable hydraulically. Various types of hydraulic systems maybe employed, and, in the present instance, the system shown comprises asource of motive fluid under a predetermined substantially constantpressure. Thus, the fluid source may consist of a pressure-responsivevariable-delivery pump, of the type shown in the patent to Snader etal., No. 2,299,235, issued October 20, 1942. A1- ternatively, the fluidsource may consist of a conventional gear pump 8 taking fluid through aninlet line 3 from a tank or sump III in the machine base 2, anddelivering a substantially constant volume of fluid to a pressure lineII, and an adjustable working pressure relief valve [2 for directing anyexcess fluid, not required to maintain the desired maximum workingpressure, from the line H through a branch line I3 back to the sump. Thepump 8 may be driven at a constant speed by an electric motor (notshown) under the control of a start and stop switch I4.

Fluid under pressure from the line I I is adapted to be suppliedreversibly under the control of a direction valve I and through lines isand II to alternate ends of a hydraulic actuator I8. This actuator alsomay be of any suitable type. and in the present instance comprises astationary cylinder I9 fixed in the machine base 2, and a piston 20reciprocable therein. The piston 20 has an axial rod 2i suitablyconnected through detachable means (not shown) to the carriage I.

The direction valve I5 (see Fig. 2), in its preferred form, comprises arectangular body 22 mounted with the machine base 2, and formed with avalve bore 23 and with ports connected to the lines II, I6 and I! andbranches of an exhaust line 24. Reciprocable in the bore 23 is a valveplunger 25 of the spool type formed with two axially spaced peripheralrecesses 28 and 21. In the intermediate or stop position, the valveplunger 25 acts to block all of the valve passages so that the actuatorI8, and hence the carriage vertically-spaced guide lugs 43 separated bya I, is locked against movement. In the opposite end positions, theplunger 2! acts respectively to connect the lines I6 and I1 reversiblyto the pressure and exhaust lines II and 24 so as to eflect translationof the carriage I in one direction or the other.

The direction valve I5 is self-centering and of the solenoid-actuatedtype. In the form shown. two tubular end caps 23 are bolted to oppositeends of the valve body 22 in axial alignment with the bore 23'. Twoextension rods 23 of reduced diameter are connected to'opposite ends ofthe valve plunger 25. and extend axially through the end caps 28.Slidable on each rod 23 within the associated cap 28 are two spacedcollars 33 urged apart by a coil compression spring 3i. The outermostcollar 30 abuts against the end wall of the cap 28, and the innermostcollar abuts against the adjacent end of the valve plunger 25 and isadapted to engage the adjacent end of the valve body 22. It will be seenthat the springs 3|, acting through the innermost collars 30, tend tolocate the valve plunger 25 in central position when the plunger is notheld in either end position by external force.

Two valve actuating solenoids 32 and 33 have their armatures pivotallyconnected respectively to the outer ends of the extension rods 23. Uponselective energization of the solenoids 32 and 33, the valve I5 can bereversed into either end position. If both solenoids 32 and 33 aredeenergized, the valve I5 will return into and be maintained in centralor neutral position. An electric control circuit is provided for thesolenoids 32 and 33, and comprises mains 34 and 35 adapted to beconnected to a suitable source of electrical energy. A master start andstop switch 36 is inserted in the main 34 for controlling the startingand stopping of the table operation. Selective energization of thesolenoids 32 and 33 is under the control of a two-position reversingswitch 31. In its opposite positions, the switch 31 serves to connectthe solenoids 32 and 33 respectively through lines 38 and 33' across themains 34 and 35.

Operation of the switch 31 to 'efi'ect reversal of the direction valveI5 at the ends of the working range is controlled from the carriage I.More particularly, the direction control means includes a switchactuating means incorporated as part of a unitary'control panel 40, andarranged for operation by spaced dogs or cams H and 42 mounted on thefront of the carriage I for adjustment along a longitudinal; T-slot 43to determine the extent and location of the working range ofreciprocation.

The control panel 40 comprises a main body 44 having a rectangular baseplate 45, with mounting pads 46 came rear face adapted to be bolted orotherwise suitably secured to the front of the machine base '2. The body44 is additionally formed substantially at the four corners of the plate45 with upper and lower forwardlyextending arms or projections 41, andwith a central vertical portion presenting flat parallel guide surfaces48 at opposite sides. Formed integral with and projecting forwardly fromthe front face of the central body portion are two flat guide surface50. A flat rectangular mounti"; plate 5| is secured to the front of thebody 44 against the lower corner projections 41, and has a narrow upwardextension disposed against the lugs 43. The lower marginal edge portionof the plate 5I is turned inwardly to define a horizontal flange 52. Arectangular housing 63, open at the rear and having walls substantiallyclosed at the iront, sides and ends, is removably secured in positionabout the body 44, and serves to enclose the Various operatinginstrumentalities oi the panel 40.

The direction control means comprises two parallel switch actuatingplungers 56 and 55 which extend through and are guided longitudinallyfor vertical movement in bushings 56 fixed in aligned openings 51respectively in the arms All at opposite sides of the panel body M. Theupper ends of the plungers 5d and 55 project outwardly through the topend wall of the housing 53, and are provided with follower rollers 58adapted for engagement respectively by the reversing cams 4H and 42 onthe carriage 1. Two rectangular pawl blocks 59 are secured respectivelyto the plungers 543 and 55 for movement therewith, and are disposed insliding engagement with the opposite guide surfaces 38. The plungers 56and 55 are normally urged upwardly and outwardly by two coil compressionsprings 66. In each instance the spring 63 encircles the plunger, andabuts at its opposite ends respectively against the lowermost arm ll andthe movable block 59. A stop collar Si is secured to the reduced lowerend portion of the plunger, and is adapted for engagement with the lowerarm ll to limit the upward movement of the plunger under the iniluenceof the spring 66 when not depressed by the associated one of the" cams Mand 32.

The reversing switch 31 is mounted on the front of the base 2 within thelower portion of the panel housing 53, and has a forwardly projectingoperating shaft 62. Secured intermediate its ends to the shaft 62 is atraveling beam 63. The op posite ends of the beam 83 extend beneath thelower ends of the actuating plungers 5 i and 55, and are provided withscrew abutments 6% adjustably threaded therethrough for alternateengagement respectively by the plungers.

The switch 31 is self-maintained in either position of adjustment, withone end or the other of the traveling beam 63 in relatively elevatedposition. of its movement, the reversing cam approaching the controlpanel 49 will engage and depress the adjacent switch actuating plunger,and thereupon the lower end of the latter will engage the underlyingscrew abutment 65 to reverse the switch 31. Thus, the carriage i will bereciprocated continuously in an automatic cycle until the start and stopswitch 38 is opened to interrupt the electric circuit controlling thereversing valve 15. When the circuit is interrupted, both solenoids 32and 33 will be deenergized, and the springs 3! will center the valve l5to stop the operation.

Means is also provided for manually reversing the switch 31 at any timein the course of travel of the carriage l. Preferably, this meanscomprises a lever 65 rotatably supported intermediate its ends on a stud66 fixed to the front" of the mounting plate 5!. The ends of the lever65 are formed on their lower sides with upwardly and outwardly inclinedbearing faces 67 which are disposed in operative position over twoforwardly projecting pins 68 respectively on the blocks 59, and whichare adapted to be in contact with said pins when the plungers 54 and 55are in fully elevated position. A gear 69 is secured to the lever 85 foroscillation therewith on the stud 66, and meshes with a gear 70rotatable on a stud 1| also fixed to the front of the As the carriage Inears either end mounting plate 5|. The stud H and a sleeve 11 on thegear 10 extend through the front wall of the housing 53, and are held inassembled relation by a washer I3 and screw H. A hand lever Hi, normallylocated in neutral position by a spring detent I6, is rigid with thesleeve I2, and afiords means for oscillating the lever 55.

It will be evident that upon actuation of the hand lever 15, the lever65 will depress one or the other of the plungers 55 and 55 to reversethe switch 3? independently of the control by the carriage cams Ail and42. The arrangement is such that rotation of the hand lever 15 to theright will cause movement of the carriage l to the right, and rotationof the lever to the left will result in corresponding movement of thecarriage to the left.

Included in the control panel 40 is the speed control means which ismanually adjustable to determine the rate at which the carriage I willbe translated. The rate may be varied from a predetermined minimum orrelatively slow speed progressively through the speed range to apredetermined maximum or relatively high speed to suit the particularrequirements of the machining operation to be performed. Preferably, thespeed control is effected by varying the speed of operation of the drivemotor for the carriage I.

In the hydraulic type of transmission herein disclosed, the speedcontrol means may suitably comprise an adjustable orifice valve Tl whichis inserted at a suitable point in the hydraulic system to govern thepressure in the line I l, and thereby the volume of fluid delivered tothe hydraulic actuator It. In the present instance, the orifice valve His inserted in the exhaust line 28 to throttle the fluid displaced fromthe cylinder 59, and consequently it determines the back pressure in thesystem resisting movement of the carriage. It will be understood thatthe back pressure is reflected through the actuator id to the pressureline H so that an increase in back pressure will tend to eiTect apressure rise in the line H to cause the by-passing of more fluidthrough the valve 12, and a decrease in back pressure will tend toeffect a pressure drop in the line to cause the spilling of less fluidthrough the valve 92, thereby indirectly controlling the volume of fluidsupplied to the actuator for propelling purposes.

The orifice or throttle valve 11 preferably is of the sliding type, andcomprises a bore 18 opening vertically through the central portion ofthe panel body Q6, and connected through passages in the plate 65 withthe exhaust inlet line 24 and an outlet line 19 leading to the sump 10.Another passage opens from the upper end portion of the bore 13 to adrain line 80. The lower end of the bore 18 is closed by a plate 8|. Avalve sleeve 82 is fixed in the bore '18, and is formed withlongitudinally spaced internal annular grooves 83, 84 and 85 openingthrough sets of radial ports 86, 81 and 88 respectively to the lines243, T9 and 80. Slidably adjustable in the sleeve 82 and projecting fromthe upper end thereof is a valve plunger 89 formed with a suitable flowpassage of adjustable efiective area for connecting the internal grooves83 and 84. In the present instance, the plunger 89 is formed with twodiametrically opposite longitudinal metering grooves 90. The lower endsof these grooves are of uniform cross-section and in constantcommunication with the outlet ports 81, and the upper ends thereof aregradually tapered and adapted to provide an adiustable restrictedorifice connection with the inlet ports 88. when the plunger 89 is inits lowermost position. as shown in Fig. 3, the upper tips of thegrooves 99 are barely in communication with the ports 99 to provide anorifice flow area of maximum restriction, resulting in an extremely slowcarriage traverse. As the plunger 891s elevated, the orifice flow areais progressively enlarged to increase the rate of carriage traverse.

Suitable means is provided for selectively adjusting the position of theoriflce valve plunger 89 in accordance with the desired-rate of carriagetraverse during the normal working stroke. Preferably, this meanscomprises an actuating rod 9| extending slidably through alignedbushings 92 in the spaced lugs 49 for longitudinal adjustment inparallel relation to the valve plunger 89. The plunger 89 and thecontrol rod 9| are suitably interconnected for joint longitudinalmovement. In the present instance, a yoke 93 is rigidly connected to theupper end of the control rod 9|, and has spaced parallel arms 94engaging in transverse grooves 95 formed in opposite sides ofthe upperend of the valve plung er 89. The lower portion of the control rod 9| isformed with an intermediate section 96 of reduced diameter, and an axialstem 91 extending through the flange 52. Rigidly secured to the rodsection 96 is a cam follower arm 99 which extends outwardly throughregistering vertical.

slots 99 in the mounting plate and the front wall of the housing 53. Acoil compression spring I99 enci cles the stem 91, and is seated at itslower end against the flange 52. The upper end of the spring I99 engagesagainst the end of the rod section 96, and tends to urge the rod 9|upwardly in 'a direction to increase the orifice flow area in the valve11.

Means is provided for adjustably restraining the upward movement of therod 9| under the influence of the spring I99 tocontrol-the position ofthe valve plunger 99. In the present instance, this means comprises arotary disk cam I9I suitably mounted on the plate 5| and locatedexternally at the front of the panel housing 53 for convenient access tothe operator. The cam I9I is formed with an axial hubor sleeve I92 supported for rotation on an outwardly projecting stud rigidly anchored, asby riveting, to the mounting plate 5|. A hand lever I94 is keyed to thehub I92 to provide means for manually adjusting the cam I9I.. A washerI95 secured to the outer end of the stud I93 by a screw I96 engages theouter end of the hub I92 to confine the cam I9I in position.

The inner face of the cam I'9I (see Fig. 8) is formed about the hub I92witha recess I91 having an internal spiral cam surface or face I98increasing progressively in radial dimension through 360 to provide athrow equal to the maximum normal adjustment of the orifice valve 11.The outer end ofthe cam follower arm 98 on the control rod 9| extendsinto the recess I91, and is rounded on the top to wipe against the camsurface I99. It will be evident that when the cam I9I is adjusted tobring the high, point a of the cam surface I99 into engagement with thefollower 98, the control rod 9| will be retracted against the force ofthe spring I99 to position the valve 11 for maximum orifice restrictionor minimum flow area, thereby causing the carriage I to travel at theminimum rate. Upon adjusting the cam I9I progressively in a clockwisedirection as viewed in Fig. 1, the recession oi the cam surface I98 willpermit the spring I99 to shift the rod 9| upwardly, and thereby adjustthe valve 11 in flnely graduated increments to decrease the orificerestriction and effect a corresponding increase in the rate of carriagetraverse. When the low point b of the cam surface I98 engages thefollower 98, the valve 11 will be positioned to eifect the maximum rateof carriage traverse. In the velocity diagram of Fig. 9, wherein theordinates represent velocity and the abscissas represent distance, theminimum and maximum rates of normal carriage traverse are indicated bythe lines o-a and -b-b, and an intermediate rate is indicated by theline 0-0.

A clamp I99 is provided for releasably securing the cam I9I in selectedposition of adjustment. The outer face of the cam I9I is provided withsuitable graduations II9. coacting witha stationary pointer I on theclamp I99 to indicate the speed setting. 1

To prevent or minimize shock and to insure that the carriage reversalwill always occur with a negligible variation at a predetermined point,the rate of traverse is decelerated to a predetermined fixed low speedas the carriage I nears the end of its stroke in either direction andimmediately prior to reversal, regardless of the normal rate of workingtraverse. As a result, the overrun of the carriage I, after eachactuation of the direction control means by one or the other of thereversing cams 4| and 42, will be constant in extent regardless of thesetting of the cam I9I. Deceleration is efiected by reducing the speedof the carriage drive motor, and in the present instance this isaccomplished by automatically adjusting the orifice valve 11 from itsnormal preset position 'to a position of increased flow restriction inthe path of the fluid exhausting from the actuator I8. Substantiallyconcurrently with reversal of the switch 31, the valve 11'is released,and automatically returned by the spring I99 to its normal position soas to accelerate the speed of the carriage I back to the plate having ashaft H6 at the upper end rotatably mounted in a lug I I1 and a bearingplate I I8 on the associated block 59.

During normal traverse of the carriage I, the

reversing cams 4| and 42 are spaced from the control unit 49, andconsequently both reversing plungers 54 and 55 are in elevated position,with the pawls II4 bearing against opposite sides of the block H2 inspaced relation above the abutment shoulders I I3. At the end of eachworking stroke, one or the other of the reversing plungers 54 and 55will be depressed by the associated cam on the carriage, depending onthe direction of movement, and the pawl 4 carried by the plunger willinitially move along the block H2 and in the continued movement of theplunger.

will ultimately engage and carry with it the underlying abutmentshoulder II3 to depress the rod 9|. Due to the lost motion between thepawl H4 and the abutment shoulder II3, the valve 11 will be adjusted toefiect carriage deceleration only during the movement of the reversingplunger immediately preceding reversal of the switch 31. The extent ofthe lost motion is variable and determined by the normal setting of thecam IIlI. For relatively high speeds, the extent of lost motion iscomparatively small so that deceleration will be started shortly afterthe cam contacts the follower roller 58, and will continue through acorrespondingly long range as required to reduce the speed to thedesired minimum. For relatively slow speeds, the extent of lost motionis comparatively large so that deceleration will be started at a laterpoint in the carriage travel, and continue through a comparatively shortrange. Consequently, the extent of carriage travel immediately precedingactuation of the reversing switch 31, available for deceleration, variesin accordance with the setting of the speed control cam II and hencewith the amount of deceleration that is required. This is clearlyindicated in the velocity diagram of Fig. 9 wherein the various lines aato c-c, representing different speeds, merge at different points withthe deceleration curve b-d. The rate of deceleration is controlled bythe shape of the cams 4| and 42, each of which has a curved cam face II9of selected form, and adapted to ride against the follower roller 58 ofthe associated reversing plunger.

At the end of the deceleration, the active pawl IE4 is automaticallydisengaged from the underlying abutment step or shoulder I I3 to permitimmediate return of the valve TI to normal position so that, uponreversal, the carriage I will not continue to travel at slow speed, butwill be accelerated immediately to the normal rate of traverse. Themeans for this purpose comprises two throw-out cams I20 adjustablymounted on the plate in the path of the respective pawls H4. Thethrow-out cams I20 consist of plates, each of which is formed with adownwardly and outwardly inclined cam face I2i adapted to be engaged bya forwardly projecting lug I22 on the free end of the associated pawl II 4, and which are secured to the mounting plate 5! side-by-side forlateral adjustment toward and from each other. It will be evident thatthe cams I20 may be spread or brought closer together to center themaccurately in relation to the pawls I I4 and to vary the point in themovement of the plungers 54 and 55 at which the pawls will be disengagedfrom the block H2 on the valve actuating rod 9|. Consequently, the speedsetting of the valve I1 for reversal of the carriage and the end pointof deceleraton in relation to the actuation of the switch 31 are subiectto adjustment.

Ihe operation of the power transmission will be evident from theforegoing description. Briefly described, the rate of normal traverse ofthe carriage l is sub ect to adjustment and determ ned by the setting ofthe cam IIJI. The cam l mits the maximum speed of the carriage I andalso determines the point in the carriage traverse at which decelerationcommences pr or to each carriage reversal. The location of the dogs 4|and 42 on the carriage I determines the extent of the working range ofreciprocation. and the points at which carriage reversal is to occur,with allowance for a constant overrun. As the carriage nears the end ofits working stroke in one direction, for example to the right. thelefthand cam 4|, which at that time is approaching the control unit 40,will depress the adjacent reversing plunger 54 against the force of thespring 10 60. As the plunger 54 continues to move inwardly, at a ratedetermined by the shape of the cam face H9, the associated pawl Ill willengage the underlying shoulder I I3 on the block II2 to shift the valveI1 downwardly with the plunger to decelerate the table at apredetermined rate and to a predetermined extent, depending on thesetting of the speed control cam I 0|. In the final inward movement, thelower end of the plunger 54 will engage the underlying screw abutment 64on the walking beam 63 to reverse the switch 31, and substantiallyconcurrently therewith, or slightly before, the cam I 2| will disengagethe active pawl II4 to release the valve 11 for return. movement tonormal position. Reversal of the switch 31 serves through selectiveenergization of one or the other of the solenoids, in this case thesolenoid 32, toreverse the valve I5 and thereby institute movement ofthe carriage I to the left. At the end of the reverse movement, theforegoing operation will be substantially repeated, except that in. thisinstance the right-hand cam 42 will depress the plunger 55 to reversethe switch 37. By reason of the constant overrun due to the momentum ofthe carriage after the direction control means is actuated, the pointsof carriage reversal are accurately defined, and the proper adjustmentof the dogs 4| and 42 may be quickly and accurately accomplished,regardless of the speed setting of the control cam IIII.

I claim as my invention:

1. A power transmission for a reversible translatory machine elementcomprising, in combination, reversible power drive means for.translating said element, speed control means associated with said drivemeans and being selectively adjustable to effect translation of saidelement at any one of difierent predetermined rates during normaltraverse, cam means for adjusting said speed control means, reversingmeans automatically operable upon translation of said element into apredetermined position to efiect reversal of said drive means andthereby reversal of translation of said element, lost-motion trip meansautomatically operable by said reversing means to actuate said speedcontrol means independently of said cam means and thereby deceleratesaid element to a predetermined low rate of translation immediatelyprior to said reversal regardless of the selected rate of normaltranslation, and means for disengaging said lost-mot on trip means fromsaid speed control means to reestablish said rate of normal translationimmediately subseouent to sa d reversal.

2. A power transmission for a reversible translatory machine elementcomprising, in combination, reversible power drive means for translatingsaid element, speed control means associated with said drive means andbeing selectively adjustable to effect-translation of said element atany one of different predetermined rates during normal traverse,electric means automatically operable upon translation of said elementinto a predetermined position to efiect reversal of said drive means andthereby reversal of translation of said element, and trip meansautomatically operable to adjust said speed control means to deceleratesaid element at a relatively slow rate to a predetermined low rate oftranslation immediately prior to said reversal regardless of theselected rate of normal translation, and being disengageable from saidspeed control means to effect acceleration of said element at arelatively fast rate back to the selected normal rate immediatelysubsequent to said reversal.

. rates during normal traverse.

3. A power transmission tor a reversible translatory machine elementcomprising, in combination, reversible power drive means for translatingsaid element, self-maintaining speed control means associated with saiddrive means and being selectively adjustable to effect translation ofsaid element at any oneof different predetermined direction controlmeans automatically operable upon translation of said element into apredetermined position to eii'ect reversal of said drive means andthereby reversal of translation of said element, releasable meansautomatically operable by said direction control means to adjust saidspeed control means to decelerate said element to a predetermined lowrate of translation immediately prior to said reversal regardless of theselected rate of normal translation. and means operable at the end ofsaid deceleration to disengage said last mentioned means from said speedcontrol means.

4. A power transmission for a reversible machine element comprising, incombination, drive means for translating said element and including aspeed control member adjustable to regulate the speed of movement ofsaid element, spring means acting on said member to urge said member inone direction to change said speed, selectively adjustable cam meansdirectly coacting with said member to limit variably the movement ofsaid member by said spring means in said one direction, while permittingmovement of said member in the other direction, latch meansantomatically operable upon movement of said element into apredetermined position to actuate said member in said other directioninto a predetermined position of adjustment regardless of the selectedadjustment of said cam, and means for automatically disengaging saidlatch means from said member upon movement of said member into saidpredetermined position of adjustment. Y

5. A- power.transmission ior. a reversible machine element comprising.in combination, a body,

drive means for translating said element and including a speed controlmember adjustable in said 12 movement of said member by said springmeans in said direction while permitting movement of said member in thereverse direction, and means having a lost-motion connection with saidmember and being automatically operable upon movement of said elementinto a predetermined position to engage and move said member in saidreverse direction into a predetermined position of adjustment, theextent of the lost-motion in said connection varying in accordance withthe adjustment of said cam.

7. A power transmission for a reversible machine element comprising, incombination, hydraulic drive means for translating said element andincluding a speed control valve slidably reciprocable to regulate thespeed of movement of said element, an actuating rod connected to saidmember for movement therewith, a coil compression spring encircling saidrod and acting thereon to urge said member in a direction to increasesaid speed, a rotary cam mounted for manual adjustment and having aneccentric recess defining an internal spiral cam face, and a camfollower fixed on said rod and projecting laterally therefrom into saidrecess for engagement with said cam face, said cam serving to limit the-movement of said member by said-spring in said direction whilepermitting movement. of said member in the reverse direction, and meansfor moving said member in said reverse direction independently of saidcam into a predetermined position of adjustment. j

8. A power transmission for a reversiblemachine element comprising, incombination, a body;

drive means for translating said element and including a speed controlmember slidably reciprocable in said body. to regulate the speed ofmovement of said element, an actuating rod slidable in said body inparallel relation'to said control member and connected at one end tosaid member for movement therewith, a coilcompression spring encirclingsaid rod and acting thereon body to regulate the speed of movement ofsaid element, spring means acting to urge said member in one directionto increase said speed,fselec-' tively adjustable cam means coactingwith-said member to limit variably the movement thereof by said springmeans in said one direction while permitting movement of said member inthe other direction to decrease said speed. means automatically operableupon movement of said element into a predetermined position 'to actuatesaid member in said other direction against'the action oi said springmeans into a predetermined posito urge said memberin a direction toincrease said speed, a rotary cam mounted on said body for manualadjustment and having an eccentric.

recess defining an internalspiral cam face, a cam follower fixed on saidrod and projecting laterally therefrom into said recess for engagementwith said cam face, said cam serving to limit the movement of saidmember by said spring insaid'direction while permitting movement of saidmember in the reverse direction, and means autotion of adjustmentregardless of the selective adjustment'of said cam means, and means forrendering said last mentioned means ineffective to further control saidmember upon movement of said member into said predetermined position ofadjustment.

6. A power transmission for a reversible machine element comprising, incombination, drive means for translating said element and including aspeed control member slidably reciprocable to regulate the speed ofmovement of said element, spring means acting to urge said member in adirection toincrease said speed, a rotary cam mounted for manualadjustment and having an eccentric recess defining an internal spiralcam face, a cam follower movable with said member and projecting intosaid recess for engagement with said cam face. said cam serving to limitthe matically operableupon movement of said e1ement into a predeterminedposition to move said member in said reverse directionjinto apredetermined position of adjustment. 1

9. A power transmission for a reversible machine element comprising,incombination, drive means including a direction control whichisreversible to effect reversal of said; element in opposite directionsand which has an operatin shaft and an oscillatory walking beam fixedintermediate the ends on said shaft, two adjustable abutments onopposite ends of said beam, two

spaced cams adapted to be adjustably mounted on said element, two spacedparallel actuating plungers slidably mounted for longitudinalreciprocation, said plungers being arranged for alternate engagement atone end respectively by said cams as said element is moved into oppositelimit positions, for operative engagement at the other and respectivelywith said abutments, and spring means actlng'on said plungers to urgesaid plungers away from'said beam into idle position in the paths ofsaid cams, and stop means for deter- 13 mining the positions of saidplungers, said cams having configurated cam faces for imparting apositive and graduated rate of movement to said plungers.

10. A power transmission for a reversible machine element comprising. incombination, drive means including a direction control which isreversible to effect reversal of said element in opposite directions,and which has an operating shaft and an oscillatory walking beam firedintermediate the ends on said shaft, two spaced independent camsadjustably mounted on said element, two spaced parallel actuatingplungers slidably mounted for longitudinal reciprocation, said plungersbeing arranged for alternate engagement at one end respectively by saidcams as said element is moved into opposite limit positions. and forengagement at the other end respectively with opposite ends of saidbeam, spring means acting to urge said plungers independently andnormally into predetermined positions in the paths of said cams, andmanual means operable at will to actuate either of said plungersindependently of each other and of said cams.

11. A power transmission for a reversible machine element comprising, incombination, drive means including a direction control which isreversible to efiect reversal of said element in opposite directions andwhich has an operating shaft and an oscillatory walking beam fixedintermediate the ends on'said shaft, two spaced cams adjustably mountedon said element, two spaced parallel actuating plungers slidably mountedfor longitudinal reciprocation, said plungers being arranged foralternate engagement respectively by said cams as said element is movedinto opposite limit positions, and for operative engagement respectivelywith opposite ends of said beam, two coil compression springs actingrespectively to urge said plungers into position for engagement by saidcams, a rocking lever supported intermediate its ends for oscillatorymovement and having oppositely extending arms arranged for engagementwith said plungers and adapted upon oscillation to retract one or themediate the ends on said shaft, two spaced cams adjustably mounted onsaid element, a stationary body. two spaced parallel actuating plungersslidably mounted in said body for longitudinal reciprocation. saidplungers being arranged for alternate engagement at one end respectivelyby said cams as said element is moved into opposite limit positions, andfor engagement at the other end respectively with opposite ends of saidbeam, two blocks secured to said plungers for movement therewith andslidably guided on opposite sides of said body and each having alaterally projecting pin, two coiled compression springs seated againstsaid body and encircling said plungers and acting respectively againstsaid blocks to urge said plungers into idle position for engagement bysaid cams, means for limiting the extent of movement of said plungers bysaid springs, a rocking lever supported intermediate its ends on saidbody for oscillatory movement and having oppositely extending armsarranged for engagement with said pins and adapted upon oscillation toretract one or the other of said plungers against the force of saidsprings, and a hand element eared to said lever, whereby actuation ofsaid hand lever in either direction will effect reversal of said elementto travel in the same direction.

13. A power transmission for a reversible machine element comprising, incombination, drive means for translating said element and including aspeed control member slidably reciprocable to regulate the speed ofmovement of said element, an actuating rod connected in parallelrelation to said control member for movement therewith and having anabutment shoulder, spring means acting to urge said member in adirection to increase said speed, manually adjustable means acting tolimit movement of said member by said spring means while permittingmovement of said member in a direction to decrease said speed, a plungermounted in parallel relation to said member, spring means acting to urgesaid plunger toward idle position, a pawl hinged to said plunger andadapted upon engagement with said shoulder to actuate said rod in saidother direction, a cam adjustably mounted on said element and having aface for engaging said plunger to adjust the latter in opposition tosaid last mentioned spring means, and means for automaticallydisengaging said pawl from said shoulder upon movement of said plungerinto a predetermined position by said cam, whereby to permit said firstmentioned spring to return said control member into the positionnormally determined by said manually adjustable means.

14. A power transmission for a reversible machine element comprising, incombination, drive means for translating said element and including aspeed control member slidably reciprocable to regulate the speed ofmovement of said element,

an actuating rod connected in parallel relation to said control memberfor movement therewith, spring means acting to urge said member in adirection to increase said speed, manually adjustable cam means actingon said member to limit movement thereof by said spring means whilepermitting movement of said member in a direction to decrease saidspeed, a block fixed to said rod and having an abutment shoulder, anactuating plunger slidably mounted in parallel relation to said member,spring means acting to urge said plunger toward idle position, a pawlhinged to said plunger for movement therewith and adapted uponengagement with said shoulder to actuate said rod in said otherdirection, a cam adjustably mounted on said element and having agraduated face for engaging said plunger to adjust the latter in saidother direction in opposition to said last mentioned spring means, andmeans for automatically disengaging said pawl from said should-er 'uponmovement of said plunger by said cam into a predetermined position,whereby to permit said first mentioned spring to return said controlmember into the position normally determined by said manual cam means. I

15. A power transmission for a reversible translatory machine elementcomprising, in combination, reversible power drive means for translatingsaid element, speed control means associated with said drive means andbeing selectively adjustable to effect translation of said element atany one of diflerent predetermined rates, direction control meansincluding an electric reversing switch and operable upon translation ofsaid element into a predetermined position to eflect reversal of saidswitch and thereby reversal of said drive means, releasable detent meansmovable with said direction control means and adapted for coaction withsaid speed control means to effect deceleration of said element to apredetermined low rate of translation immediately prior to saidreversal, and means for disengaging said detent means from said speedcontrol means at the end of said deceleration, said speed control meansthereupon being selfadjustable to eflfect acceleration of said element.

16. A power transmission for a reversible machine element comprising, incombination, drive means for translating said element and including adirection control member operable to reverse the direction of movementof said element and a speed control member adjustable to regulatethespeed of said movement, spring means acting on to urge said directioncontrol member into idle' position, a cam adiustably mounted on saidelement and adapted to actuate said direction control means intooperative position to reverse said drive means, releasable detent meanscarried by said direction control member and adapted for engagement withsaid speed control member to adjust the latter in said other direction,and means for automatically disengaging said detent means from saidspeed control member upon movement thereof into a predetermined positionof adjustment. 7 1

17. A power transmission for a reversible machine element comprising, incombination, drive means for translating said element and including adirection control member which is reversible to effect reversal of saidelement in opposite directions, and a speed control member adjust-'ableto regulate the speed of said translation,

spring means acting to urge said speed control member in a direction toincrease said speed, a rotary cam mounted for manual adjustment andhaving a recess defining an internal cam face, a cam follower movablewith said speed control member and projecting into said recess forengagement with said cam face, said cam serving to limit the movement ofsaid speed control memher by said spring means in said direction andpermitting movement in the reverse direction, an actuating memberautomatically operable upon movement of said element through apredetermined distance at the end of the translation of said element inone direction to reverse said direction control member, and a releasablelostmotion connection between said actuating member and said speedcontrolmember, said last mentioned connection being operable after theinitial movement of said actuating member to pick up and adjust saidspeed control member in said reverse direction into a predeterminedposition of adjustment to eflfect deceleration of said element priortoreversal and at-the end of said deceleration to release said speedcontrol member for return movement into coaction with said rotary cam.

18. A power transmission for a reversible machine element comprising, incombination, drive means including a direction control which isreversible to effect reversal of said element in opposite directions andwhich has an operating shaft and an oscillatory walking beam fixedintermediate the ends on said shaft, two adjustable abutments onopposite ends of said beam, two spaced cams adapted to be adjustablymounted on said element, two spaced parallel actuating plungers slidablymounted for longitudinal reciprocation, said plungers being arranged foralternate engagement at one end respectively by said cams as saidelement is moved into opposite limit positions, and for operativeengagement at the other end respectively with said abutments, springmeans acting on said plungers to urge said plungers intoidle position inthe paths of said cams, said cams having configurated cam faces forimparting a positive and graduated rate of movement to said plungers,speed control means for determining the speed of said drive means andnormally biased in a direction to increase said speed, adjustablevmeansfor determining the maximum speed of said drive means, and meansoperable by either ofsaid plungers for actuating said speed controlmeans to reduce said speed to a predetermined minimum prior to eachreversal of said operating shaft.

19. A power transmission for a translatory machine element comprising,in combination, a reversible hydraulic motor for driving said element, asource of fluid including pressure responsive means operable to vary thevolume of fluid supplied to said motoras required to maintain asubstantially constant pressure, and means automatically operable inresponse to'the movement of said element to control the back pressure offluid displaced from said motor whereby to influencesaid pressureresponsive means to control said supply of fluid to said motor,comprising a reciprocable adjustable orifice metering valve interposedin the path of" fluid flow from said motor, a parallel actuating rodconnected to said valve for movement therewith,-sprin'g means acting onsaid rod in a direction. to increase the flow area through said valve,"cam 'means coacting with said rod for adjustably limiting the maximumopening of said valve under the influence of said spring means, a 1reciprocable plunger parallel to said rod and operable to shift said rodagainst the action of said spring means, and cam means adapted to bemounted on said element for actuating said plunger.

CHARLES Z. MONROE.

REFERENCES crrnn The following references are of record in the me ofthis patent:

UNITED STATES PATENTS Farley fl Jan. 9, 1945

